Objectives:

We investigated whether CD4 cell counts or antiretroviral therapy were determinants of persistent Staphylococcus aureus nasal carriage and whether methicillin-resistant (MRSA) and Panton-Valentine Leukocidin (PVL) positive strains were circulating in a population of HIV-patients in The Netherlands. Furthermore, we compared the genetic structure of S. aureus isolated from HIV patients with the previously determined population structure of healthy individuals with S. aureus nasal carriage.

Methods:

Between February 2004 and June 2005 all HIV patients visiting the outpatient department of Erasmus University Medical Centre (Rotterdam, The Netherlands) were asked to participate in this study. Participants were interviewed and screened for S. aureus carriage using two quantitative nasal swab cultures. According to an earlier validated culture rule, two carriage patterns were distinguished: non-or-intermittent versus persistent carriage. Potential determinants of persistent carriage were evaluated using logistic regression. S. aureus strains were tested for the presence of mecA and PVL by PCR. The genetic structure of S. aureus was determined by AFLP-analysis.

Results:

For 443 patients two cultures were available of which 131 (29.6%) were persistent carriers. Male sex [odds ratio (OR) 2.22; 95% confidence interval (CI), 1.323.73], current smoking (OR 0.58; 95% CI, 0.380.90), Pneumocystis jiroveci pneumonia (PCP) prophylaxis (OR 0.39; 95% CI, 0.160.97) and antiretroviral therapy (OR 0.61; 95% CI, 0.380.98) were independent determinants of persistent carriage. CD4 cell counts were not associated with persistent carriage (P = 0.629). Only two strains were mecA positive (1.2%) and no PVL positive strains were detected. The population structure of S. aureus strains isolated from HIV patients appeared to be strongly overlapping with that of S. aureus isolates from healthy individuals from the same geographic region.

Conclusions:

HIV patients have an increased risk of persistent nasal carriage of S. aureus compared to healthy individuals. Male sex (+), smoking (-), PCP prophylaxis (-) and the use of antiretroviral therapy (-) are independent determinants of persistent S. aureus nasal carriage in this cohort of HIV-patients. No PVL positive strains were found to be circulating and the prevalence of MRSA was low. No unique S. aureus clones specific for this cohort were identified.